This invention pertains generally to bicycles and particularly to an improved front or rear fork end fitment connector. For purposes of illustration, the invention will be described in detail as applied to a rear fork connector and it will be apparent that it may likewise be applied to a front fork end fitment connector utilizing the same principles.
Typically, a bicycle frame has a rear fork including upper frame stays and lower frame stays arranged in pairs on opposite sides of the rear wheel. These diverge upwardly and forwardly from the rear axle and are welded or otherwise secured to the frame at locations behind the seat post and the crank hanger respectively.
At each end of the rear axle, the two stays are secured as by welding to a rear fork end fitment connector having an open ended slot in which the rear axle is mounted. Similarly, there is a front end fitment connector of somewhat another size, on each side of the fork having an open-ended slot in which the front axle is mounted.
Each fitment connector has a thickened hub portion surrounding the axle-engaging slot. The hub portion has opposite raised surfaces which extend about one-sixteenth inch outwardly from the main body portion of the connector to thereby provide opposite bearing surfaces for an external axle nut and an internal axle lock nut respectively. These raised bearing surfaces at opposite ends of the thickened hub must be perfectly flat and parallel to one another to provide solid, flatwise seating engagement with the respective nuts and prevent loosening in service. Further, to prevent unsightly scratching and corrosion of these outer hub surfaces, they are buffed and chromium-plated.
These fitment connectors take the entire load applied by the frame to the wheel, and are therefore subject to very high stresses. To obtain the required strength, they have customarily been made of steel; and to provide the thickened hubs, they have been manufactured by conventional hot forging techniques which involve costly tools and dies, expensive mechanical and heat energy, and substantial investments in heavy machinery and labor. The additional step of chromium plating the outer hub surfaces, as described above, adds to the cost. Further, to provide the precisely parallel flat surfaces at the ends of the hubs, and the precisely dimensioned slots, they have typically been machined after the forging operation. All these factors result in a high manufacturing cost per unit even when they are made in very large production quantities.